Piezoelectric Inkjet Ejection State Detection via Alternating Waveforms
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Solution Overview
Problem
Existing liquid ejecting apparatuses, such as ink jet printers, face ejection abnormalities due to increased viscosity of liquids, leading to inaccurate determination of ejection states and decreased image quality, as existing techniques struggle to accurately assess the ejection state when viscosity is slightly increased.
Innovation Solution
A liquid ejecting apparatus with a driving signal generator producing specific waveforms to displace a piezoelectric element in alternating directions, and a detector to analyze vibrations remaining after the displacement, ensuring the difference between time periods aligns with natural vibration periods, enhancing the accuracy of ejection state determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple single-direction driving signal is used to displace the piezoelectric element, then the device complexity is reduced, but the measurement precision of ejection state determination deteriorates when liquid viscosity increases
Solution Approach 1:
The patent applies periodic action by using a driving signal that alternates between first and second waveforms in sequential time periods. The first waveform displaces the piezoelectric element in a first direction, and the second waveform displaces it in a second direction opposite to the first. This periodic alternation creates distinct vibration patterns that enable accurate detection of ejection state even when liquid viscosity increases, resolving the contradiction between simple signal structure and precise measurement.
2Measurement precision
If the detection time period is extended to capture more vibration data, then the measurement precision improves, but the loss of time increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the detection time period to start immediately after the second time period and lasting for a predetermined duration. The driving signal structure itself (with its specific waveform alternation) is designed to generate detectable vibrations within this predetermined window. This allows the system to capture sufficient vibration data for accurate ejection state determination without requiring extended detection periods, thus balancing measurement precision with time loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution improves the accuracy of ejection state determination even with slightly increased viscosity, reducing printing quality degradation by amplifying the difference in vibration amplitudes, thus ensuring consistent and high-quality ink ejection.
Implementation Method 1
drives a piezoelectric element provided in an ejector included in the liquid ejecting apparatus by a driving signal to displace the piezoelectric element
Implementation Method 2
the ejection state of a liquid in an ejector is determined based on the period of vibrations produced in the ejector driven by a driving signal
Data Source
AI summary
A liquid ejecting apparatus including an ejector configured to eject a liquid with displacement of a piezoelectric element, a generator configured to generate a driving signal, which has a first waveform, for displacing the piezoelectric element in a first direction, and a second waveform, for displacing the piezoelectric element in a second direction opposite to the first direction, and a detector configured to detect a vibration remaining in the ejector in a detection time period starting after completion of the second time period. The difference between a duration from the first time point to the second time point and a duration that is a natural number times the period of a vibration produced in the ejector is shorter than one quarter times the period of the vibration produced in the ejector.